Temperature regulation



June 3, 1941 c, w, ss 2,244 631 TEMPERATURE REGULATION Filed Sept. 29, 1938 Snnentor lu1rence W N cssellll WW AM attorney Patented June 3, 194i UNITED STAT s PATENT OFFICE I r azussr TEDIPERATURE REGULATION Clarence W. Nessell, Dayton, Ohio, assignor to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn., a corporation of Delaware Application September 29, 1938, Serial No. 232,367

' Claims. (01. 236-11) The present invention relates to temperature regulation in heating, ventilating, and air conwherein all zones are open to admit heat or fluid medium when the condition in all zones is, satisfactory. This being the principal object of my invention, its ultimate purpose is to make it possible to distribute any surplus heat or conditioning medium to all of the zones after the con- In such systems individsource of fluid medium and efiective to open and close their respectivezones whenever any instrumentis calling for fluid medium, fluid medium being circulated to allthe zones when they are satisfied depending on a condition at the primary source of fluid medium.

A further object. is the provision of a zone control system having air distributing ducts with dampers therein; and individual zone control instruments,- the dampers being so constructed and controlled that they remain open unless their respective control instruments are satisfied and at the same time at least one other control instrument is calling for conditioned air.

A further object is the provision of a zone control system having an air heating device, air distributing duets with dampers therein, and individual zone control instruments controlling the trol instruments all become satisfied or to relieve any excess pressure or the like at the fluid treating apparatus. In the past it was customary to provide what is commonly known as a relief zone to accomplish these purposes, this practice entailing usually an overrun of temperature in the relief zone and needless wastage of energy expent in the fluid medium treating apparatus.

Other objects of my invention are to eliminate the need of a relief zone in zone type heating and conditioning systems but at the same time to accomplish the functions of a relief zone in an improved manner whereby the disadvantages characteristic of a relief zone are avoided.

Another object is to provide a control arrangement for zoned systems of the character described wherein individual zone control instruments control their respective zones and a common source of fluid medium for conditioning purposes, all the zones being opened to admission of fluid medium when all the instruments are satisfied.

dampers, in combination with an air circulating fan for forcing air to all zones when all control instruments are satisfied, all the dampers being open under such conditions.

A further object is the provision of a zone control system wherein individual zone control obtains during daytime operation, all zones opening when-all'are satisfied and wherein all zones remain open during the night, control of the system being from a singleinstrument.

Another object is to improve the efliciency of air conditioning systems generally.

The single flgure of the drawing represents diagrammatically a zone control system embodying my invention therein.

While I have chosen to describe as a representative form of my invention its embodiment in a warm air type heating system, it is expressly understood that it is equally applicable to other types of systems as referred-to above.

Referring to the drawing, the letters A, B, and

C designate various zones of a building which may be individual rooms or which may be groups of rooms. Numeral l indicates generally a warm air furnace which may be of conventional type having a combustion chamber 2 and an air heating space I formed by a jacket 4, the upper part of which forms the furnace bonnet. The combustion chamber 2 has a stack 5 for conveying burnt gases of combustiontherefrom and an air distributing duct 6 communicates with the furnace bonnet for conveying heated air therefrom.

The distributing duct 6 has branch conduits I, l,

by a furnace fan l2 driven by an electric motor i3, the fan having a suction conduit M which may connect with a return air duct from the various zones of the building, and the fan discharges into the air heating space 3 for forcing air therethrough and into the duct 6 as shown.

In the particular embodiment of the invention disclosed, heat may be supplied by a conventional gas burner ii, the gas being supplied through a conduit I6 which may connect with a gas main, not shown. Interposed in the conduit |6 is a gas I control valve I! which preferably is of the elec- 20 comprising a strip of bimetal 2| cooperat-.

ing with a fixed electrical contact 22 so as to form a switch. Thesafety pilot 26 may be of a type well known in the art and has for its purpose to shut down the system in the event of extinguishment of the pilot flame as I will explain more in detail during the description'of operation following.

Disposed in the branch conduits l, 6, and 9 are automatic dampers 26, 26, and 21, respectively. These dampers 26, 26, and 21 are operated by electric spring return type damper motors indicated respectively at 26, 26, and 36. Referring to the operating motor 26, it comprises a shaft 3| upon which the damper 25 is mounted for energization of the motor thedamper is moved to closed position as indicatedby the damper 26,

the arm 32 moving against the tension of spring 24. The damper remains in fully closed position as long as the motor is energized and immediatemovable blade 44 which cooperates with fixed electrical contacts 46 and 46.

Numeral 34 indicates a day-night thermostat having a clock or other timing mechanism 43. Thermostat 94 consists of a conventional bimetal element 41 for actuating flexible switch blades 86 and 36 cooperating with fixed electrical contacts 31 and 36. Thermostat 34 is set at a relatively high setting during the day so as to normally remain closed and its setting is automatically changed to 60 for example for night operation.

Further control of the system is provided by a control instrument generally indicated at 66 comprising mercury switches 6|, 62, and 63, all of which are actuated by a helical thermostatic element 64 responsive to temperature of air be-- ing heated within the bonnet 4. The thermostatic element 64 is mechanically connected to the mercury switches so that they are sequentially operated in order, the switch 63 being actuated first, the switch 6| next and the switch 62 last from their positions as shown in the drawing as the temperature within the bonnet 4 rises.

Numeral 66 indicates generally-an electrical relay which I have disclosed as comprising a coil winding 66 which cooperates with an armature or a solenoid for actuating electric switch blades 61, 66, 53 and i6 respectively, the switch blades being mechanically connected to the armature or solenoid as indicated by .the broken line 66. The switch blades 61, 63, 63 and i0 cooperate with fixed electrical contacts 6|, 62, 63 and II respectively.

Power for my entire system may be supplied through line conductors 64 and 66 connected -to a suitable source of external alternating current power, not shown, and power at suitable ly upon deenergization oi the motor the spring 24 rotates the motor and shaft 3| so as to move the damper to open position as indicated by the position of damper 21 associated with zone C. Inasmuch as the damper motors 23 and 33 and their various associated structures may pref.

- erably be identical with motor 23'they need not be described in detail.

fixed electrical contacts to the other, that is, the

blade 36 moves with a snap action in both dlrections. Contact 33 is the hot contact and with which the blade 36 engages at a predetermined temperature, and contact 31 is the cold contact to which the blade 36 snaps at a predetermined lower temperature, the diiference between the two temperatures being some suitably chosen differential such as 2". or the like. The thermostats 34 and 35 are preferably identical with the thermostat 33 and need not be described in the same detail. The thermostat 34 has a movable blade 4| which cooperates with fixed electrical con,- tacts 42 and .43 and the thermostat 36 has a voltage for the various control instruments and devices may be supplied by a step-down transformer indicated generally at 66. The transformer 66 comprises a primary winding 61 and a secondary winding 66, the primary winding having a greater number of turns than the secondary as-conventional in this type of transformer. The transformer 61 is connected to the line conductors 64 and 66 by wires 63 and I0, respectively. I will next describe the complete operation of my system, tracing the various electrical circuits which I employ to bring about the various sequences and results which constitute in part the novelty of my invention.

With the parts in the position shown, the thermostats 33 and 34 in zones A and B are satisfied and the thermostat 36 in zone C is shown as calling for heat to be supplied to that particular zone. The movable blade 44 of thermostat 36 is engaged with fixed contact 46. thereby completing an electrical energizing circuit for the coil winding 66 as follows: from the fixed contact 46 through a wire H, wire 33, contact 33, blades 36 and 36, contact 31, a wire I2, coil 66, wire .13,- wire I4, secondary winding 63, wire 16, and wire 16 back to the thermostat 36. Energization of the coil winding 66 causes closure as shownof all of the switches 61, 63, 69, and I0. Closure of switch 63, as will presently be seen, controls, an electrical circuit whereby all of the motors 28, 29, and 30 may be energized. The energizing circuits for motors 23, 23, and 36 have a portion in common comprising the wire I6 (which is connected to all the thermostats), the

is energized through the following circuit: Ii'which connects to the thermostat a. through wire secondary 8, wire 14, switch 80, wire it, wire ll, motor 28, wire ll, fixed contact 3|, switch blade ll, and through the thermostat It back to wire ll. Motor 2! is energized by a similar parallel branch circuit comprising the common circuit portion traced above, through wire II, wire ll, motor 2|, wire I, fixed contact 42, and blade 4| of thermostat 34. Thus it is seen that switch it controls the energizing circuits of both motors 2; and 29 as well as the motor 3|. Aswlll be seen by reason of the fact that the blade 44 of thermostat II is in engagement with contact 46 rather than contact 45, a circuit through the motor 30 is not completed through the wires l2 and '3. From the above description, it will beseen that dampers 25 and, 26 are in their closed positions as shown and the damper 21 is in its 1!, mercury switch Si, wire ll, safety pilot 2.

wire 8'I,'valve l1, and wire 88 back to the wire Ii. As soon as the valve l1 opens, burner operation begins and heat is supplied as long as any one thermostat is' calling for heat as will presently be made clear. As soon as the temperature within the space 3 has risen to ahigh enough value for suitable heating in a zone or. zones calling for heat-mercury switch 53 will be operated to'its closed position by element 54 completing the aircult for the fan motor which is as follows: from line conductor 65 through the fan motor, wire 89, switch 58, wire 9|, mercury switch II, wire ii, and wire 92 back to line conductor 64. A- forced circulation of heated air is supplied by thefan l2 as soon as the mercury switch "is closed, and continuesthereafter as long as any thermostat is calling for heat to be supplied to its respective zones. with the parts in the posigagement with contact 40 and into engagement with contact 45 interrupting the above described circuit through coilwlnding it and causing all of the switches 51, i l, I! and II to open. Opening of switches 51 and II will interrupt the above described circuits which control the valve i1 and the fan It, thereby terminating the supply of fuel to burner ii and stopping the fan I2. Opening of switch II will create a gap in that portion of the energizing circuits for motors 28, 29, and

which is commonto all of them as above described. All of the motors will now be deenergized and the dampers 25, 26, and 21 will be moved'to their open positions. Thus upon all of thezone thermostats becoming satisfied, all the zone-dampers are immediately moved to their i open positions.

In apparatus of this particular type, when the heating plant is shut oil and the fan stopped upon all of the thermostats becoming satisfied, there may be a substantial amount of residual heat in the combustion chamber, for example the combustion chamber 2. Inasmuch as noair is being circulated by the fan II to carry away this residual heat, the temperature in the space I may rise to a relatively high value even higher than the temperature at which mercury switch Si is operated. In my particular arrangement, at a relatively high value of temperature affecting the element 84, the mercury switch 52. will be closed completing an auxiliary circuit for the fan motor It as follows: from line conductor 65 through the motor [3, wire It, wire 93, mercury switch I2, and wire 92 back to the line conductor 64. The fan ilwill now' beoperated so as to force air to circulate through the space ,3 carrying away the residual heat therefrom and distributing it to all of the zones through the various branch conduits I, I, and 9. Thus not only will the temperature within the bonnet 4 be prevented i'rom rising to an undesirable and unsafe value, but the residual heat will, instead of being tion'shown on the drawing the bonnet temperature has not risen enough to close switch II.

The mercuryswitch 5i, as above described, is

in the circuit of the control valve l1 and forms a high limit switch which will be opened by the element I4 so as to discontinue heating at a pre- .will continue until thermostat 35 becomes satislied and blade 44 moves into engagement with contact 45. If before thermostat 35 becomes satisiied either (or both) of the thermostats 3i and v34 indicate a need for heat in their respective zones, it will cause its respective damper to be opened. For example, should thermostat I4 call for heat, blade 4| will move. into engagement with fixed contact 43. The'fabove described energizing circuit for motor 29 will now be interrupted and, as previously described, the spring return arrangement will'move the damper 20 to the open position so that heated airwill be supplied to zone B as well as zone C; The thermostat 14 calling for heat'at this-time will bring about no change in the present operation of the heating equipment.

Now assuming that thermostats 33 and 34 have remained satisfied and thermostat 3! also becomes satisfied, blade 44 will move out of en through the satisfied thermostats 33 and 34 rewasted, be'evenly distributed to the various zones whereby the thermostats therein will remain at the satisfied position for a longer time. In this manner, I successfully utilize the residual heat at the furnace in all thezones rather than disposing of it by wasting it in causing a great overrun of temperature in a relief zone as was commonly done in the past. Thus I avoid the additional equipment necessary for a relief zone used for disposal of surplus heat and instead I promote economy by advantageously using this surplus heat. It is to be appreciated that my invention may be applied to a system having any number of zones and by reason of the fact that I distribute thesurplus heat to all of the zones, there is no appreciable overheating of any of them such as would take place in a single relief zone. Y

Assuming now that all of the thermostats having remained satisfied for a period of time, a single thermostat, for example thermostat 35, calls for heat, again taking its position asshow'n in the drawing.- Burner and fan operation will now be initiated in the manner already described and at the same time closure of switch 59 will complete energizing circuits for the motors 28 and 2s spectlvely, as has already been described above. Thus upon thermostat 3i calling for heat the dampers 2i and II will immediately be moved into their closed positions as shown on the drawing so that heated air will be supplied only to the zone C as set forth at the beginning of the deelement 41 of thermostat 94.

scription of operation. Similarly, upon any zone thermostat calling for heat, coil It will be energized through thecold contact of that thermostat bringing about the above described sequence, it

being apparent of course that the cold contacts of all the thermostats are connected to wire I! so that the'thermostats may be connected in parallel between wires 80 and 15.

During daytime operation the clock thermostat N at its relatively high setting has remained in a position with both of its pairs of contacts closed, at a predetermined time in the evening determined by the setting of the clock ll, the setting of the settings of the thermostats 33, 34 and 35 so that at this time the thermostat 84 will open its contacts. Obviously, therefore, none of the zone thermostats 33, 34 or ll energizes the relay ll because of the interruption in the circuit connections between wires I2 and II occasioned by the opening of both pairs of contacts of thermostat ll. Thermostat 94 controls the heating of the entire building during the night, and when the temperature of the building has fallen to' a value which may be 60", blade it will engage fixed contact ll. When the temperature has fallen to a value which may be 1 or 2 lower for example, blade II will engage contact 01, it being understood that the two pairs of contacts or thermostat M are operated sequentially. when both pairs of contacts have been made a circuit is completed for energizing the relay which is as follows: from. blade ti, through contact 81, wire II, winding it, wire II, wire ll, secondary winding 08, wire ll, wire ll, blade 44 of thermostat 35, contact l, wire H, wire I, contact and blade it back to blade ll of thermostat M. It will be seen that this circuit just described extends through the thermostat 3!, which will be in closed position-because-the temperature .of the building has fallen to substantially 60 which is materially below the setting of the zone thermostats. It will be understood of course that in addition to this circuit last described, parallel circuits for enerswitches II, II, II and II into closed position.

Heating will be initiated and will proceed in the same manner as has already been described in connection with control from the individual zone thermostats. Inasmuch as all of the zone thermo stats are in engagement with their cold contacts, none of the zone damper motors will'be energized and the zone dampers will remain open and they will so remain all during the night, that is, during the time that the thermostat 94 is in control. At the time that relay 5! is energized and switch blade ll engages contact I I, a maintaining circuit for relay II is completed as follows: from element 41 of thermostat N, through wire 49, switch blade ll, fixed contact ll, wire 23, wire 12, winding 56, wire 13, wire ll, secondary winding 68, wire it, wire ll, blade 44 of thermostat 3i, fixed contact l8, wire ll, wire 89, contact 98, blade 96 back to It will be seen that this last described circuit is independent of blade 06 and contact 81 of thermostat 84, and that therefore relay II will not be deenergized until the building temperature rises to a value above 60, the temperature at which blade It engaged flxed contact 98. Obviously, therefore, the thermostat' 94 has a fixed operation differential by reason of which chattering of the relay 5! is eliminated and which might otherwise result from vibration of the contacts of ordinary type thermo-v stats having only one pair of contacts. Whenever the temperature does rise-above 60, relay 55 will be deenergized and heating will be discontinued in the same manner as described in connection with individual zone control operation, all zones as previously pointed out remaining in ope position all during day operation. From the foregoing the unique and advantageous results which I gain by use of my invention and which I have particularly pointed out, should be clearly apparent to those skilled in the art. I reduce the amount of equipment which is generally necessary in similar systems known to the prior art and in doing so I at the same time gain results whereby substantial economies of operation are eflected. All of the equipment which I employ is of a type well known by those skilled in the art to be of a simple and sturdy nature and not likely to get out of order or to require the need of servicing by expert technicians or the like.

while I have disclosed a single embodiment and application of my invention, it is to be appreciated that the fundamental concept thereof is capable of a wide range of structural manifestations and applications. I therefore desire protection by Letters Patent of the United States limited not by my disclosure but only as determined by the scope of the appended claims. I claim as my invention: .1. In a temperature control system for a building having a plurality of zones, in combination, means for heating a fluid heat transfer medium, means for conveying said heated fiuid medium to said zones, an electrical device controlling the supply of fluid medium to each zone,

each device permitting the passage of fluid when deenergized, and preventing the passage of fluid when energized, a thermostat in each zone responsive to the temperature of the air therein having a pair of stationary contacts and a movable contact, said movable contact engaging a first stationary contact when calling for heat, and engaging a second stationary contact when said thermostat is satisfied, a relay for controlling said-heating means and saiddevices, said relay when energized permitting operation of said heating means and energization ,of said devices, and when deenergized preventing operas tion of said heating means and energization of said devices, a source of electrical energy, an energizing circuit for said relay including said source of energy, said relay, any of said first conling the supply of fluid medium to each zone,

each device permitting the passage of fluid, when deenergized, and preventing the passage of fluid- 'ergizing circuit of its sponsive to the temperature of the air therein,

a a pair of switches associated with each said thermostat, and selectively operable thereby, energizing circuits for said control devices, a relay for controlling all said energizing circuits, a relay energizing circuit, one of said pair of switches being eflective to closesaid relay energizing circuit, and the other of said pair of switches being eifective to close the energizing circuit for its associated control device, and circuit connections such that each of said device energizing circuits includes only one said thermostatically operated switches, and each of said thermostatically operated switches carries energizing current for only one of said devices- 3. In an air conditioning system of the zone type, in combination, a building divided into a plurality of zones, a source of conditioned air,

electrically controlled damper means for each,

zone controlling the supply of air thereto, each said damper means assuming open position when deenergized, switch means in each of said zones movable between two controlling positions, a relay, a switch controlled by said relay, an energizing circuit for said relay, means whereby each zone switching means is operable when in one of said two controlling positions to close said enengizing circuit, and an energizing circuit for each damper means including said relay controlled switch and only one of said zone switch means, each zoneswitch means being in the enmeans and being operable when said circuit is otherwise closedto complete closure of said cir-' cuit when said switch means is in its second circuit controlling position.

. 4. In a temperature control system for' a building having a plurality 0! zones, in combination, means for heating a fluid heat transfer medium, means for conveying said heated fluid medium to said zones, an electrical device controliated zone damper ling the supply of fluid medium to each zone, I

each device permitting the passage of fluid when deenergized, and preventing the passage of fluid when energized, a thermostatic switch in each zone responsive to the temperature of the air therein and movable between two controlling positions in accordance with the value of said temperature, relay means for controlling said heating means and said devices, an energizing cin- ,cuit for said relaymeans, means whereby each zone switching means is operable when in one of said two controlling positions to close said energizing circuit, and an energizing circuit for each said controlling device including only one of said thermostatic switches, each thermostatic switch being in the energizing circuit of the controlling device in its associated zone and being operable when said circuit is otherwise closed to complete closure of said circuit when said thermostatic switch moves to its second circuit controlling position.

5. In a temperature control system for a building having a plurality of zones, in combination, means for heating a fluid heat transfer medium,

means for conveying said heated fluid medium to said zones, and'electrical device controlling the supply of fluid medium to each zone, each device permitting the passage of fluid when deenergized, and preventing the passage of fluid when energized, a thermostat in each zone responsive to the temperature or theair' therein, each thermostat comprising a pair of switches a first of which is closed on a rise in temperature to a predetermined value and the second oi' which is closed on a fall in temperature to a predetermined value, a control switch, a relay for closing said control switch when said relay is energized, an energizing circuit for each said device including said control switch and the first switch 01' the thermostat in its associated zone, said thermostat being the only one of said thermostats in said energizing circuit, and an energizing circuit for said relay including all 01' the second switches 01' said thermostats in parallel. F

CLARENCE W. NESSELL. 

